The memory sub-system isn't designed for fast/slow pages, but having the
information available would be v. useful.
>From time-to-time, the question pops up; "I've installed extra
memory, and Linux runs slower!", and answer is (nearly) always due to
pages not being cached (not enough tag-ram, etc). If Linux could
display a warning for this condition, I'd vote for it.
The page allocation routines could also be modified to try and avoid
giving out slow pages, and start paging out when 'fast' pages become low
- a very simple solution, and probably wouldn't work v. well...
> > No, I don't know the difference between local and system memory, and I
> "Local" would be on the motherboard, "system" on another board. Before memory
> modules (SIPPs and SIMMs), when you wanted more memory, you added an ISA (or MCA?)
> card with memory chips on it. Bandwidth was, um, suboptimal.
Would there still be systems out there which have this archiecture? I
somehow doubt it, but watch out for the up coming NUMA machines. Each
'node' will have local memory, but will be able (at a cost) to access
memory on other 'nodes' (a single address space).
Regards,
markhe